1. Field of the Invention
This invention relates to a method of processing a sealing surface of a casting to eliminate casting defects present on or in the vicinity of the sealing surface for an improvement in the sealing performance, and further to a grindstone suitable for use in the method.
2. Description of the Prior Art
Cylinder blocks for internal combustion engines are generally made by casting a metal, for example. One surface of a casting is finished to serve as a sealing surface. A sealing member such as a gasket is attached to the sealing surface of the casting, and a sealing surface of another member such as a cylinder head is pressed against the attached sealing member so that the two members, that is, the casting and the another member are airtightly assembled together. If a casting defect is present on the sealing surface or in the vicinity thereof, airtightness and accordingly, the sealing performance between the two members will be reduced.
Chemicals are conventionally applied to the sealing surface of the casting to prevent the reduction in the sealing performance due to the casting defects present on the sealing surface or in the vicinity thereof. The chemicals are penetrated into the casting defects such as blowholes so that the casting defects are filled up or impregnated with the chemicals.
However, it is sometimes difficult to impregnate the casting defect with the chemicals depending upon its size, configuration, etc. Furthermore, it is difficult to eliminate the casting defects of the casting used under high temperature conditions, for example, the engine cylinder block.